Using alternate fuel sources for vehicles is becoming a popular option in many countries. Vehicles capable of consuming different fuel types are referred to as “flex fuel vehicles” (FFV). At the time of this writing, there are approximately 5 million flex fuel vehicles in the U.S.A.
Limited production and increasing prices of petroleum derived gasoline motivates consideration of alternative fuels. For example, ethanol is an alternative automotive fuel that is generally made from the fermentation of relatively abundant renewable crops like corn, sugar cane, sugar beets, and cellulose. Ethanol is a liquid fuel with similar properties to gasoline. Ethanol can be readily mixed with gasoline and used in an internal combustion engine. Mixtures of up to 10% ethanol can be used in a standard automobile engine without modification. Flex fuel engines and vehicles can use any mixture of gasoline and ethanol.
The percentage of ethanol in fuel is commonly referred to by the letter “E” followed by the percentage of ethanol; the remaining content is gasoline. Therefore, E100 is pure ethanol, E0 is pure gasoline, and E10 is a mixture of 10% ethanol and 90% gasoline. The percentage of ethanol affects the performance of an engine and the vehicle using it. The energy content of E100 is approximately 76,000 BTUs while typical E0 fuel has approximately 114,000 BTUs. The higher the E percentage, the more fuel is needed to produce the same amount of energy. Therefore, an increase in the E percentage will usually result in a decrease in the vehicle mileage range for a given quantity of fuel, for example a full tank.
The E percentage can change significantly after a refueling, especially when switching fuel types. Using existing technology, a mileage range value on the vehicle dashboard display will not immediately update itself based on a new fuel blend or mixture in the fuel tank. The vehicle may have to be driven many miles or sometimes run through a full tank of fuel before the mileage range is accurate.
Conventional fuel range calculations do not account for the type of fuel in the vehicle. Most conventional vehicle mileage range displays use the average fuel economy for a previous driven distance, such as the last 25 miles, to calculate the mileage range value. This can lead to an inaccurate mileage range display after fueling if a significant amount of lower or higher energy fuel is added to the tank because the range is calculated from the energy content of the previous fuel mix rather than the present fuel mix. For example, if the fuel is changed from E0 to E85 it can have a significant impact on the fuel consumption value and it would take about 25 miles after switching fuel types to make a difference in the mileage range value calculation.
Accordingly, it is desirable to have a way to calculate the mileage range value for vehicles capable of using various fuel mixtures, and to update the mileage range displayed on an on-board display element to a more meaningful value corresponding to each fuel mixture used after each refueling event. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.